A method of cutting a billet into blanks is disclosed in, for example, {circle around (1)} Japanese Patent Laid-Open Publication No. 2001-321871, “Method of Press Molding Aluminum-based-composite Disc-like Parts.” A method of feeding blanks heated to a predetermined temperature is disclosed in, for example, {circle around (2)} Japanese Patent Laid-Open Publication No. HEI-6-198413, “Solid-liquid-coexisting-range Die Casting Method.”
The press molding method of the conventional art {circle around (1)} will be described below with reference to FIG. 12.
First, alumina (Al2O3) powder is formed into a predetermined shape in advance, being a porous alumina compact. Then, the compact is reduced and a molten aluminum alloy is infiltrated into the reduced porous structure, producing an aluminum-based-composite billet 101.
The aluminum-based-composite billet 101 is successively cut by a cutter 102 to a predetermined thickness t, forming a blank material 103 of the aluminum-based composite. Then, the blank material 103 is placed on a metal mold for molding.
In the cutting method of the conventional art {circle around (1)}, however, the cutter 102 cuts the aluminum-based-composite billet 101 with the blade of the cutter 102 wearing away soon, increasing the frequency of replacement of the cutter 102, and increasing production cost. The increased frequency of replacement of the worn-out cutter 102 lengthens the stop time of the cutting machine, resulting in poor productivity. Further, a machining allowance corresponding to the width dimension of the cutter 102 is required, reducing the yield of the expensive aluminum-based composite.
The die casting method of the conventional art {circle around (2)} comprises the following steps:
(a) first, a round bar is cut at a predetermined length, and a cut material is put into a metal container with its internal surface coated in advance with a mold release agent;
(b) then, the material put in the container is heated in a heating furnace to a solid-liquid coexisting temperature range of the material. After the heating, the container containing the material is put out from the furnace and is carried to a sleeve insertion opening; and
(c) finally, the container is upset (inverted 180°), letting only the material fall into the sleeve, thus injecting the heated material into a mold cavity.
The use of the die casting method, however, requires the step of inverting the container after heating the container to let the material fall from the container, taking time for handling the material, and resulting in poor productivity. Further, the cutting work of cutting the round bar to a predetermined length of materials, producing a plurality of materials from the single round bar takes time. Especially with a round bar of a hard-to-cut material, the work takes time, increasing production cost.